Battle of the sexes? More like battle of the thermostat.

Men are from chilly Mars, yet they apparently run hotter — while women feel left out in the cold.

One study got to the bottom of this phenomenon and proposed an explanation for why half the population feels like they’re constantly bundling up.

Looking at how 28 healthy men and women responded to temperatures between 62 and 88 degrees, researchers noted an “arctic” shift in the women, who had cooler temperatures.

The reason behind this difference is more than skin deep.

“Skin temperatures really didn’t vary that differently than the men,” lead study author Robert Brychta told The Post. “What we did find was that … the women tended to have a lower resting metabolic rate than the men, and that’s related to their smaller body sizes.

“The smaller person, whether it’s a man or a woman, is going to produce a lower amount of heat,” he added.

Resting metabolic rate is the calories your body burns at rest to maintain basic life functions like breathing, blood circulation and temperature regulation.

Men tend to have 23% higher resting metabolic rates because they have greater lean muscle mass that burns more calories at rest than fat tissue. More muscle mass generates more body heat.

Brychta, of the National Institute of Diabetes and Digestive and Kidney Diseases, did note a possible exception to this principle.

“We also found that people who have higher levels of body fat have greater thermal insulation,” he said. “The women tended to have a higher level of insulation from their higher body fat percentage as a group.”

Researchers found that women’s heat production scaled with body size, and resistance to heat loss was related to body fat.

“If you have a smaller woman compared to a larger man, they’re definitely going to feel colder,” Brychta explained. “A smaller man that’s very thin and has a lower body fat percentage, then they also would feel colder than a bigger person.”

Ultimately, Brychta and his team concluded that how warm or cold someone feels comes down to three factors: body size, type and composition.

Previous studies have also suggested that women may be colder because they have naturally higher core temperatures, making cold air feel even cooler to the body.

Several external factors can affect our body temperatures as well, with stress levels, cigarette use, diet and hormonal birth control all playing a role.